DeBlog: Why Do Mosquito Bites Itch?

It’s almost the official start of summer and that means, mosquito season is already here. We do everything we can to prepare but somehow we still find ourselves scratching away at our bug bites after a night outside in Minnesota. Holly Hoffman and Mindy Sticha of New Prague want to know, why do mosquito bites itch?

“It’s more like a little infection because the mosquito injects a little bit of material into the skin,” said Dr. Bruce Bart, of Hennepin County Medical Center. “You have to have had a few number of bites, than you start to become allergic to them.”

Our bodies produce histamine in reaction to the saliva injected by the mosquito.

“It’s produced by cells as an immune system reaction to any type of injury,” Bart said. “That histamine causes the swelling because the nerves are affected, and that causes the intense itching.”

Children are more susceptible than adults to have an itchy reaction because we become immune to the enzymes in the mosquito saliva as we get older.

“We produce antibodies that protect the skin — if people continue to get bitten over time they become desensitized,” he said.

And if you do get itchy from a mosquito bite, blame the female.

“The males don’t bite or inject,” Bart said. “The female mosquitoes are the only ones that need a blood meal.”

While it’s quick relief to scratch a mosquito bite, the more you scratch the more histamine is produced.

“Any rubbing or scratching makes it worse,” he said. “Ice packs help slow the reaction a lot or any creams with antihistamine will help block it.”